Pneumatic tool.



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APPLICATION FILED NOV. 11, 1901.

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110.736,555. Patented August 1s, 190e.

Nrn Sa'rns 'PATENT OFFICE.

CHARLES HENRY SHAV, OF DENVER, COLORADO.

PNEUMATIC TOOL.

SPECIFICATION forming' part of Letters Patent No. 736,555, dated. August18, 1903.

Application filed November ll, 1901. Serial No. 81,937. (No model.)

To @ZZ la7/1,0111, it may concern: to designate corresponding partsthroughout Be it known that I, CHARLES HENRY SHAW, the various figuresof the drawings. a citizen of the United States, residing at Den- Thecylinder 20 is of a length correspond- 5 5 ver, in the county ofArapahoe andv State of ing to the desired length of stroke of the pis- 5Colorado, have invented `a new and useful ton and is adapted to receivea solid cylin- Pneumatic Tool, of which the following is a drieal piston2l. One end of the cylinder is specification. counterbored for thereception of a valve-con The invention relates to certain improvetainingbox or casing 22, adapted to fit snugly 6o ments in pneumatic tools ofthat class in within the cylinder and held from movement 1o which areciprocating piston acts upon the in one direction by an annular flange23, fitshank of a chisel or other tool. ting over the end of thecylinder, and in the One object of the invention is to so constructopposite direction by the air-pipe nipple 24, the cylinder and piston asto obtain a long which is screwed into a threaded opening in 65 strokeof the piston with a correspondinglythe side of the cylinder and entersan alining x 5 increased impact upon the tool and to more opening in thevalve-casing. In a suitable fully control theinovement ofthe pistonwith- .chamber in the valve-casing is a cylindrical out waste of the airor other fluid employed valve 25, having an annular port or passage asan actuating medium. 2G, which when in alinement with the nipple- 7o Afurther object of the invention is to pro'- opening permits the air orother iiuid to pass 2o vide an effective cushioning of the piston onfrom the nipple to and through the main port its rear stroke to overcomethe momentum of 27, leading to the controlling-valve. The the piston andprevent any direct contact bevalve 25 is normally held in the closedpositween the latter and the end of the cylinder; tion by helicalcompression-spring 28, partly 75 and a still further object is tocombine an imseated in an opening in the lower end of the z 5 provedform of valve adapted to be operated valve and having its lower end incontact with by the air or other duid when compressed by the lower wallof the valve-chamber. The the rear stroke of the piston. valve 25 is ofsuch length that its upper end Vith these and other objects in view theinprojects beyond the valve-chamber for con- 8o vention consists in thenovel construction and tact with a handle 29, carried by or forming` 3ocombination of parts hereinafter described, part of a sleeve 30, mountedon the cylinder, illustrated in the accompanying drawings, the latterbeing confined in position by the and particularly pointed out in theappended nipple 26 and having sufficient play to permit claims. itsbeing moved against the valve to open the 8 5 In the drawings, Figurelis a longitudinal same. The handle is normally held from con- 3 5sectional elevation of a pneumatic tool contact with the valve byahelical spring 3l, and structed in accordance with my invention. thevalve being operated upon by the spring Fig. 2 is a similar view, on asomewhat larger 28 is normally held in a crossed position. To scale,with the valves in different positions. place the tool in operation, allthat is neces- 9o Fig. 3 is a detached perspective view of the sary isto depress the handle and open the 4o valve for governing the admissionof the actu- `preliminary valve. The compression-spring ating fluid tothe tool. Fig. 4 is a sectional 31 acts while the tool is in use to takeup the elevation of thevalve-easing detached. Figs. shock or jarresulting from the rapidimpaet 5 and G represent, respectively, an endelevaof the piston on the shank of the tool, reduc- 95 tion andsectional view of the automatic valve ing the strain on the operator.

45 for controlling the movements of the piston. The cylinder 2O is madein two sections or Fig. 7 is a transverseseotional elevation, on isprovided with an outer jacket or casing 32, an enlarged scale, on theline 7 7, Fig. 1. extending from end to end thereof wand pro- Figs. 8,9, lO, 11, 12, 13, l-l, and 15 are views jecting slightly beyond thelower end of the 1o) similar to Fig. 7 on the sectional lines of Fig.tool for the reception and support of a tool- 5o 1, bearing theircorresponding reference-nureceiving socket 33 of a construction moremerals. fully described hereinafter. This construc- Similar numerals ofreference are employed tion of the cylinder permits of the formation ofmore perfect ports than could be accomplished by coring, the ports beingeither cast or milled in the periphery of the main cylinder 2O and theninclosed and covered by the concentric jacket 32.

The upper portion of the cylinder is counterbored to form two annularvalve-seats 34 and 35, against which iit the end and the shoulderportion of an annular valve 36. The valve is provided with a centralopening of the same diameter as the cylinder and is guided to someextent by the lower end of the valve box or casing 22, there beingbetween said valve boX or casing and the adjacent inner walls of thecylinder an annular groove or space for the reception of the upper endof the valve and forming a cylinder into which fluid under pressure maybe introduced to effect a downward movement of said valve at eachdownstroke of the piston. The lower end of the valve projects somedistance beyond the valve-seat 34 to afford sufiicient area for the airor other iiuid com.- pressed on the upstroke of the piston to move saidvalve in an upward direction, it being noted, however, that the entirearea in the lower end of the valve is much smaller than the area of theupper end of the valve, so that when both are exposed to equal pressurethe valve will be moved downwardly. In the periphery of the valve 36 areannular ports 37, 38, and 39 for directing the course of the actuatingfluid, and from the latter port lead small passages 40 to the uppersurface of the valve to admit air above the valve when the latter is tobe moved.

The various ports and passages referred to in the following descriptionare cut or otherwise formed in the cylinder wall and are clearlyillustratedin the transverse sectional views Figs. 7 to 14, inclusive.For the sake of clearness, however, the'various ports have been omittedfrom Fig. 1, their course being indicated by dotted lines extendingoutside the figure.

The port 27 leads from the primary valvechamber to a point near thelower end ofthe automatic valve 36 and when the valve is elevated, asshown in Fig. 2, permits the flow of air into the upper portion of thecylinder to move the piston downwardly. This port is divided into threeor more sections in order not to weaken the cylinder-wall, as indicatedin Figs. 7 to' 12, inclusive. When the valve 36 is fully down, this portcommunic'ates with the annular port 37 of the valve and is placed by thelatter in communication with'a port 41, leading to the lower end of thecylinder and preferably formed in two sections, as indicated in Figs. 11to 14.

Vhen air has been admitted through the port 41 to the lower end of thecylinder, the piston 21 is raised by the air-pressure until it haspassed an opening 42, formed directly through the wall of the cylinderand permitting the escape of air from the lower end of the cylinder. Thepressure of the air will impart during its brief action sufficientmomentum to the piston to carry the latter to the limit of the upstroke,the piston as it approaches the limit of its upward movement driving outthe air from the upper portion of the cylinder through an escapeport 43,which leads to the valve-chamber, at a point in line with the annularport 38 of the valve and is placed by the latter in communication withopenings or ports 44, leading to the outer air. To provide for the quickescape of the air, the port 43 is formed in four sections, giving alarge area for the passage of the air from the cylinder.

Vhen the piston reaches the lower end of the port 43, it acts as a valveto close said port. The air contained within the cylinder above the portis compressed by the upward movement of the piston until the pressure issufficient to cause the upward movement of the valve 36, which againplaces the main pressure-port 27 in communication with the upper end ofthe cylinder. The upward. movement of the piston, however, is so rapidthat the piston will pass beyond the lower end of the port 27 and enterthe chamber formed in the interior of the valve 36, the air within saidchamber forming a dead-cushion which gradually stops the movement of thepiston. The compressed air within this chamber will in eX- panding drivethe piston downwardly, imparting to it an initial movement sufficient tocarry it past the port 27, whereupon the air entering through said portwill act upon the piston and effect the completion of its downwardstroke. As the .valve 36 is in the elevated position during the downwardstroke of the piston, communication will be closed between theescape-port 43 and the outlet-openings 44, so that no air can escapefrom the cylinder through this port. its limit of the downward movementit passes a port 46, the upper end of which is at this time incommunication with the annular port 39 of the valve 36, and a quantityof the compressed air flows from the cylinder through the port 46,thence through port 39 and openings 40 to the annular chamber in whichthe valve is situated, theair acting on the top of the valve and on thebottom of the valve with equal pressure; but, as before stated, the areaat the top of the valve is greater than that of the bottom and adownward movement of the valve ensues,cutting off the flow of airthrough the port 27 to the upper end of thecylinder and openingcommunication between the eX- haust-port 43 and the outer air, inreadiness for the next upward movement of the piston. At the same timecommunication is opened between the port 27 and the port 41, permittingthe flow of air to the lower end of the cylinder and starting the pistonon its upward movement.

lIn order to further strengthen the connections between the cylinder andits jacket 32,

IOO

As the piston nears IIO the lower portion of the jacket is provided withan annular shoulder 45, on which the lower end of the cylinder rests,and the flange 23 of the valve-chamber 22 is of awidth suiiicient tooverlap both the cylinder and its jacket,wl1ile at the same time thenipple 24: also tends to prevent any longitudinal displacement.

In the lower portion of the jacket is secured a tool -receiving socket3S, into which the shank of the tool may be inserted in position toreceive the impact of the piston. In order to hold the tool in positionand at the same time to permit of its ready insertion or removal in thesocket, the shank of the tool is provided with an annular groove 46,into which extend pins 4.7, having rounded inner ends, and the heads ofsuch pins are acted upon by a curved spring 49, seated in the groove orrecess milled or otherwise formed in the periphery of the jacket 32.This structure is such as to permit of the ready changing of tools,while at the same time the tool will be held from accidentaldisplacement.

Vhile the construction herein described, and illustrated in theaccompanying drawings, presents the device in its prefered form, it isobvious that many changes in the form, proportions, size, and minordetails of construction may be made within the scope of the claimswithout departing from the spirit or sacrificing any of the advantagesof my invention.

Having thus described my invention, what I claim is* 1. In a pneumatictool, the combination of the cylinder having at one end an annularvalve-chamber of a diameter greater than the bore ofthe cylinder, saidchamber having two concentrically-disposed shoulders arranged indifferent planes, a peripherally-ported annular valve guided within thechamber and adapted to lit against said shoulders, said valve having acentral bore of a diameter equal to the bore of the cylinder and thearea of the lower face of said valve being less than the area of theupper face thereof, means for closing the upper portion of thevalve-bore to form a dead-cushion space within the valve,

a piston adapted to enter the bore of the valve after leaving thecylinder and to effect an opening movement of said valve by thecompression of air during the latter portion of the piston-stroke, thevalve-opening movement being in the same direction as that in which thepiston is traveling, a piston-controlled port leading to thevalve-chamber, longitudinal ports or passages formed in the valvebetween one of the peripheral ports and the upper end of said valve topermit the entrance of air under working pressure to said valve-chamber,and ports or passages leading through the walls of the cylinder andcontrolled by said valve.

2. In a pneumatic tool, the combination of the cylinder having at oneend an annular valve-chamber, an annular valve adapted to said chamberand having peripheral ports or passages, and longitudinal ports orpassages extending from one of the peripheral ports to the upper end ofthe valve, and a piston adapted to reciprocate in said cylinder.'

3. In a pneumatic tool, the combination of the cylinder having at oneend two concentrically-disposed shoulders 34, 35 arranged in differentplanes, a pressure-operated valve having annular ports and adapted to tagainstsaid shoulders, said valve being further provided withlongitudinal ports or passages extending from one of the annular' portsto the upper end of the valve, there being in the walls of the cylinderlongitudinally-disposed feed and exhaust ports in communica- `tion withthe annular ports of said valve, and a piston adapted to reciprocate inthe cylinder, substantially as specified.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses.

CHARLES HENRY sHAw.

Witnesses:

C. F. ScHorrELD, M. T, Goss.

